Li2O-Al2O3-SiO2微晶玻璃表面粗糙度对纳米硬度测试的影响

 介绍了纳米压痕测试技术的基础理论及纳米压痕法常用的Oliver -Pharr方法的计算原理。采用纳米压痕试验测得不同表面粗糙度的Li2O-Al2O3-SiO2微晶玻璃样品的纳米硬度、弹性模量和载荷-位移曲线。结果表明样品表面粗糙度会降低纳米压痕测试结果的稳定性、准确性和可靠性：样品表面粗糙度越小，测得的纳米硬度和弹性模量值波动越小，载荷-位移曲线重合性越高。随着最大载荷的增大，测得的弹性模量逐渐减小，其原因是压痕边缘材料发生了塑形变形。在超光滑表面样品（Ra=0.9 nm）上测得较为准确的Li2O-Al2O3-SiO2微晶玻璃纳米硬度和弹性模量值分别为8.8 GPa和7.79 GPa。纳米压痕测试结果的重合度对于评价超光滑表面完整性研究具有指导意义。

Influences of surface roughness of Li2O-Al2O3-SiO2 glass-ceramic on nanoindentation test

The basic theory of nanoindentation testing technique and the Oliver-Pharr method as one of the most useful calculation method were introduced. The hardness, elastic modulus and depth-load curve with different surface roughnesses of glass-ceramic in the Li2O-Al2O3-SiO2 system were measured by nano-indentation test respectively. The test results show that the stability, accuracy and reliability are reduced by the surface roughness: the smoother the sample surface is, the smaller the fluctuation of hardness and elastic modulus is and the higher the coincidence degree of the depth-load curve is. The elastic modulus is decreased with the increasing of the maximum load, which is caused by the plastic deformation of material. Testing results of the nano hardness and elastic modulus of glass-ceramic in the Li2O-Al2O3-SiO2 system are 8.8 GPa and 7.79 GPa respectively on the ultra-smooth surface of the sample(Ra=0.9 nm). The coincidence degree of results of the nanoindentation test is significant to express the super smooth surface integrity.